1. Field of the Invention
The invention is directed to a method and an apparatus for producing filler sticks for cosmetic sticks, such as lipsticks, and the like, in particular having a swiveling mechanism for extending the filler stick from a protective sheath, in which the filler stick is poured into a mold and after cooling setting is removed from the mold.
2. The Prior Art
Filler sticks of cosmetic sticks, such as lipsticks, and the like must have a very well-defined consistency, so that once finished, they will have the desired usage properties. In order to be applied as cosmetics, the filler sticks must have a certain softness or creaminess, yet that makes them vulnerable to mechanical surface damage and deformation.
For manufacturing such filler sticks, it is known to provide vertical, cup-shaped molds into which the molding composition is poured, and to cool the mold in order to accelerate hardening and facilitate removal of the filler sticks.
Filler sticks produced in this way are usually inserted into retaining elements. This function is performed as part of a swiveling mechanism for extending the filler stick out of a protective sheath, which is intended to protect it from the aforementioned mechanical damage, and, in an embodiment particularly preferred by the user, for swiveling it back into the sheath as well. Conventionally, the connection between the retaining element and the filler stick is produced by inserting the finished, molded filler stick form-fittingly or with frictional engagement into the cup-shaped end of the retaining element. This causes the cup-shaped end of the retaining element to encompass the end of the filler stick inserted into it, in such a way that some play remains, depending on the wall thickness of the end of the retaining element between the outer wall of the filler stick and the protective sheath into which the filler stick and retaining element are inserted. This free space can mean that at an elevated temperature, for instance when kept in a handbag placed in the sun or in the glove compartment of a car, the filler stick will bend, and then harden again once the phase of elevated temperature is ended, so that the next time the swiveling mechanism is actuated the filler stick will break, or will at least suffer substantial damage.
With relatively thick filler sticks, it is known to avoid such a play, by pressing spindle-like extensions of the retaining element into the inside of the filler stick, in order to join the retaining element to the filler stick.
Securing a filler stick to such spindles and inserting the filler stick into a cup-shaped recess are two separate operations, in addition to the actual production of the filler sticks, and the manipulations themselves carry the risk of damage to the filler stick, hence increasing the number of rejects produced. A further problem with filler sticks typically produced in vertical mold recesses is that especially when numerous mold recesses of this kind are combined into one mold block, for the sake of more economical production, it is extremely difficult to attain a desirable temperature control. Even though cooling channels, for example, are provided in the body of the mold block, the desired crystal structure that is particularly suitable for this particular application is not optimally attainable in this way.
A further problem is that because of gravity, on the one hand, and because of the prevailing temperature gradients on the other, structural irregularities occur in the conventional vertical mold recesses during cooling and hardening, which have a negative effect on the properties for use; in particular, when pigments to provide a pearly or lustrous appearance are used, undesired nonhomogeneous structures form.
Relatively thin filler sticks are typically extruded in the form of a strand, then cut and finally sharpened. When the filler sticks are cut and sharpened, they must be mechanically held, which exposes the relatively soft surface of the filler stick to the danger of being damaged. In a previously known method for producing thin filler sticks by casting methods, the casting composition is introduced via a dispensing needle introduced into the casting mold; as the fill level of the mold increases, the dispensing needle is moved from bottom to top, out of the vertical mold. This method is extraordinarily labor intensive, because it requires that each individual mold recess be individually handled during incremental filling, and moreover, still has the basic disadvantages of forming a filler stick in the axial direction.